80 lines
2.0 KiB
C
80 lines
2.0 KiB
C
#include <stddef.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "img_png.h"
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#include "../common/utils.h"
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#define BUFSIZE 1024
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const unsigned char img_png_signature[] = {0x89, 'P', 'N', 'G', '\r', '\n', 0x1a, '\n'};
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// Reads magic number and determines if data is PNG
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int png_can_decode(const uint8_t *data, size_t size) {
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if (size < 8) return 0;
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return memcmp(data, img_png_signature, 8) == 0;
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}
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struct img_png_chunk read_chunk(FILE *fp) {
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struct img_png_chunk cur_chunk;
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// Read chunk length
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unsigned char len[4];
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if(fread(len, sizeof(*len), 4, fp) < 4) {
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fprintf(stderr, "Couldn\'t read chunk length.\n");
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exit(EXIT_FAILURE);
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}
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cur_chunk.length = char_to_uint32(len);
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printf("Chunk length: %lu\n", (unsigned long) cur_chunk.length);
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// Read chunk type
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if(fread(cur_chunk.chunk_type, sizeof(*cur_chunk.chunk_type), 4, fp) < 4) {
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fprintf(stderr, "Couldn\'t read chunk type.\n");
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exit(EXIT_FAILURE);
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}
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printf("Chunk type: %.*s\n", 4, cur_chunk.chunk_type);
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// Read chunk data
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size_t chunk_size = cur_chunk.length / sizeof(unsigned char);
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printf("Chunk size: %zu\n", chunk_size);
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cur_chunk.chunk_data = malloc(chunk_size);
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if(!cur_chunk.chunk_data) {
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perror("Failed to allocate chunk data!");
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exit(EXIT_FAILURE);
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}
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if(fread(cur_chunk.chunk_data, 1, cur_chunk.length, fp) != cur_chunk.length) {
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if(feof(fp)) {
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fprintf(stderr, "File ended prematurely.\n");
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exit(EXIT_FAILURE);
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}
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fprintf(stderr, "Failed to read chunk data!\n");
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exit(EXIT_FAILURE);
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}
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return cur_chunk;
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}
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image_t* png_decode (const uint8_t *data, size_t size) {
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return NULL;
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}
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void png_destroy(struct image_decoder *self) {
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if (self) {
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free(self);
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self = NULL;
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} else self = NULL;
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}
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image_decoder_t* png_decoder_create () {
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image_decoder_t* decoder = malloc(sizeof(image_decoder_t));
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decoder->name = "PNG";
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decoder->can_decode = png_can_decode;
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decoder->decode = png_decode;
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decoder->destroy = png_destroy;
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return decoder;
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}
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